Heat treatment of tramway and other rails



W. M. MORDEY. HEAT TREATMENT OF TRAMWAY AND OTHER RAILS.

A P P L l C A T l 0 N F I L E D l U N E 2 I 9 2 Q.

Patented July 5, 1921.

2 SHEETS-SHEET l.

W. M. MORDEY. HEAT TREATMENT OF TRAMWAY AND OTHER RAILS.

APPLICATION FILED JUNE 2, 1920.

Patented July 5, 1921.

2 SHEETSSHEET 2 UNITED STATES PATENT OFFICE.

WILLIAM MORRIS MORDEY, OF WESTMINSTER, ENGLAND.

HEAT TREATMENT OF TRAMWAY AND OTHER RAILS.

Specification of Letters Patent.

Patented July 5, 1921.

Application filed June 2, 1920. Serial No. 386,029. I

1918, application No. 7752, of which theb 10 f ollowing is aspecification.

It is known that the wearing surfaces of tramway or other rails can behardened and toughened and the wearing propertles thereof improved, byheating the rails to a suflicient temperature and depth and cooling themat a moderate rate.

i The present invention has for its object to enable the heating oftramway and other rails either in situ after laying, or before laying,to a high temperature to be effected in a simple, quick and convenientmanner to enable the physical condition of such rails to be, altered andimproved, and particularly for enabling rails made of suitable steel tobe heated to a sufiiciently high temperature to admit of their beingsubsequently hardened and toughened by suitable cooling.

' For this purpose, successive portions of a tramway or other rail areheated by bringing them one after the other into the magnetic circuit ofan alternate current electroone phase or multiphase, so constructed andof such strength, that an alternating magnetic flux'will be induced ineach portion of the rail under treatment, of sutlicient value to set upeddy currents therein of such strength, aided to some extent by magnetichysteresis, as to heat the metal composing it to the temperaturerequired but not to a temperature exceeding the critical nonmagnetictemperature of the particular metal of which the rail is composed, use"being made, for this purpose, of the fact that, at this point, the

generation of heat will automatically cease to increase owing to thepermeability of the heated material being then very considerablyreduced.

Each portion of rail after'being heated to the desired temperature issuitably cooled to impart thereto the desired characteristics.

he invention can'advantageously be applied to -the heat treatment ofrails of various kinds made of iron or steel or of iron or stecl'alloys,all hereinafter included in the term ra-i or motor generator 0,

The following is a general description of the application of theinvention for the purpose set forth, in connection with which it has theadvantage that an electrical indication is given when the desiredtemperature has been attained. There is also the further advantage thatthe alternating current used in carrying out the heating process can emade to afford, according to the invention, a means of electricallypropelling the vehicle carrying the heating apparatus- -along the track,

as required by the process of the heating of the rails.

The invention will be readily understood from the following descriptionwith the aid of the accompanying drawings, wherein Figure 1 shows inside elevation and dia grammatically, rying it into practice. Fig. 2 isa side elevation showing a different construction of electro-magnet.Fig. 3 shows in transverse section a modified arrangement of the polepieces ofthe electro-magnet in relation to the rail to be heated.elevation a modified construction of electromagnet. Figs. 5 and ,6 areside elevations showing two modified arrangements of apparatus embodyingthe invention.

eferring first to Fig. 1, on a vehicle a suitable for runnin on therails b of a tramway is mounted a rotary transformer that receives,through suitable means, as for instance a trolley pole (Z, directcurrent from a trolley wire 6, or other supply conductor, and convertsit into alternate current. If asupply of alternating current isavailable either from the trolley wire 6 or otherwise, a rotarytransformer will of course not be required. Carried by the vehicle a andsupported immediately above one or each of the rails b is a powerfullaminated alternate current electro-ma net f having its poles 7" closeto the rail. uitable means are provided for adjusting the position ofthe magnet vertically in relation to the rail to suit requirements forworking and transport. For this purpose, a screw f net- 7 may extendthrough a stationary support f and be provided with an adjustingwheel 1. The winding orwindings of the electro-magnet are traversed bythe alternating current or currents received from lnduced in the headbetween the poles f neticflux being thereby of the rail 1) under andFig. 4 shows in side apparatus suitable for cari jointed to theelectro-magof the electro-magnet, the magnetic circuit being completedlocally through the head of the rail. As a consequence of this, theportion of the rail so acted on is heated by eddy currents and to someextent by magnetic hysteresis. The poles f may be of any suitable formand may be arranged to send the magnetic flux horizontally through aportion of the head of the rail, and may be tapered to concentrate theinduction as shown in Fig. 1. Or they may, as shown in Fig. 3, bearranged to send the flux through the upper portion of the rail head bfrom side to side thereof, that is to say at right angles to the lengthof the rail 1).

As the required temperature is attained, the vehicle a, is moved along,preferably at an even rate, and the heated portion of the railis allowedto cool, cooling being quickened, if necessary, as by a water spray orair blast, caused to impinge on the rail as through a nozzle 11,(Fig. 1) arranged near to the part of the rail being heated.

,The eleetro-magnet 7 may, in some cases be a multiphase electro-magnetand be formed like a straightened out circumferential portion of thestator or field of a multiphase induction motor, but preferablygi'aduated in section and in winding, to com- P Y plained. When theelectro-magnet, or part of it, is thus made, as shown diagrammaticallyin Fig. 2, it may be used to propel the vehicle a by the reaction set upbetween it and the eddy currents in the rail 1), the speed beingcontrollable, as for example by variation of the excitation of part ofthe electromagnet, or of the air gap between the poles f and the rail,or by a friction brake a (Fig. 1) on the vehi'cle.

By the extension of the electromagnet in the direction of travel, asshown in Fig. 2, the heating may be effected in a more gradual mannerover a considerable length of rail, the poles being graduated instrength, those that cause the final and greatest heatingbeing much thestronger in order to act effectively. The electro-magnet may, as

shown in Fig. 4, be made in parts mounted to turn sidewise relatively toone another, as about a joint f, or the poles in the middle portion ofan electro-magnet, such as shown in Fig. 2, may be broadenedhorizontally in a lateral direction, to suit curves in the rail undertreatment.

It is only necessary that a very short portion of the rail head shouldat any time attain the highest temperature required, so long as eachportion successively attains it.

In or associated with the winding of the electro-magnet fis placed anindicating instrument g-, which may be an-ammeter, or a voltmeter, or awattmeter, or a power factor meter, to show when the heating of the railhas reached the required temperature,

with the conditions hereinafter ex-' which will vary more or less withdifferent kinds of steel. An infallible indication of the desiredtemperature having been attained, will be given by the instrument, whichwill respond to the altered condition of the magnetic circuit.

Guided by the indication of the instrument 9, the rate of forwardmovement of the vehicle a can be controlled so that a magnetic portionof the rail Z) is constantly coming into the field of the electro-magnetwhile the portion that has been heated sufiiciently to becomenon-magnetic, or nearly so, is constantly passing out of that field. Inthis way a continuous and uniform thermal effect is produced on the railand a steady load imposed on the electrical plant used. The indicationof the instrument 9 being a sufficient guide to the proper rate offorward movement of the vehicle, it is not necessary to directly observethe rail itself, or its degree of heat. So far as is practicable, theportion of the rail that is being heated may therefore be covered orshielded in any convenient way as for instance by asbestos or othersuitable material, to lessen oxidation of the. rail and to conserveheat. Such a shield. shown at in Fig. 1, may be attached to theelectro-magnet f so that it will be moved along therewith by thevehicle. Such a shield may be arranged, as shown, to prevent the waterspray or other coooling medium used for subsequently cooling the railand issuing for example from the nozzle n, from coming in contact withthe portion of the rail that is being heated in the field of theelectro-magnet.

The successively heated portions of rail are suitably cooled, as forinstance in the manner described, for imparting to the rail the requiredcharacteristics. It will be understood that the heating of the rail, andalso the cooling of the rail, are effected in a continuous orprogressive manner and not in intermittent steps or stages.

Or, the heating of the rail may be effected partly by electro-magneticmeans as described. so as to preheat the rail to any desired temperatureup to the critical nonmagnetic temperature. and partly by sup plementaryheating means such as a suitable flame extendiug from a nozzle w so asafterward to raise the temperature of the rail to the criticalnon-magnetic temperature, or, if desired to a higher temperature. Theflame nozzle '10 will be arranged near to the magnet poles f and befollowed closely by the nozzle 12 from which the cooling medium issuesagainst the heated portion of the rail.

Afrequencysufiiciently high may be used to insure that the heat shall bemainly produced at or near the surface of the rail. The frequency may bevaried as one means of controlling the depth or penetration of the heatin the rail.

Suitable switching and controlling devices are arranged in therespective direct current and alternate current circuits to regulate thespeed, frequency and output of the rent supplied direct to the suitablesupply of electric energy is not rotary transformer or motor generator.Thus, in Fig. 1, h is a starting and controlling switch for the rotarytransformer 0; i a main switch in the rotary tranformer circuit and j acontroller for the alternate current electromagnet f, the indicatinginstrument hereinbefore referred to being shown at g.

Cooling arrangements are Or may be provided to prevent overheating ofthe poles or other parts of the electro-inagnet as for example byarranging the poles f to extend in a water tight manner, through a boxthrough which and inlet and outlet pipe p and p water is caused to flow.may be provided to minimize heating of the poles by heat radiation fromthe portion of the rail for the time being under treatment. For thispurpose the shield 76 (Fig. 1) hereinbefore referred to, made say ofasbestos cloth, may be used. The. laminae of the poles should,preferably, be insulated with very thin mica.

If a supply of alternating current is avail able either from the trolleywire 6 or other supply conductor the rotary transformer 0 is dispensedwith and the alternating curswitch 71,. If a available from an overheador other supply conductor, the alternate current required may beprovided by an alternator 1", (see Fig. 5) mounted on the vehicle anddriven by any suitable means, as for instance by an internal combustionengine a.

The electro-magnet or magnets, and the means for supplying alternatecurrent there, to, may, as in the examples shown, conveniently be on thesame vehicle.

For treating rails before they are laid, it may be convenient to fiX theelect ro-magnet or magnets and to move each rail relatively to it, asshown for example in Fig. 6, where. f is a stationary electro-magnet andb a rail carried by rollers 25 and capapble of being moved endwise belowwater nozzle n for the purpose hereinbefore described.

No claim is herein broadly made to the heating of iron or steel oralloysthereof by placing said metal in the field of an alter nate currentelectromagnet.

What I claim is z- I 1. The process for the heat treatment of a tramwayor other rail forthe purpose h herein set forth, which consists incausing the rail to pass longitudinally through a magnetic field set upbetween the magnetic poles of a powerful alternate current electromagnetso that successive longitudinal por- Also, means the poles f and a tionsof the rail will successively form between the said poles part of themagnetic circuit of the magnet core and will have induced in each ofthem in succession a magnetic-flux and consequent eddy currents, of suchstrength as thereby to become heated to the desired temperature limitedby the critical non-magnetic temperature of the metal of which the railis composed, the successive portions of the'rail thus heated beingsuccessively cooled.

2. For the heat treatment of a tramway or other rail for the purposeherein set forth, heating in a progressive manner, successive portionsof the rail to a high temperature by causing each portion in turn to bebrought into and form part of the magnetic circuit of the magnetic coreof a powerfully energized alternate current electro-magnet havingits'magnetic poles arranged near to the rail so that there will beinduced in each portion of the rail that is, for the time being, in themagnetic field, an alternating ma netic flux of sufficient value to setup in said portion of rail eddy currents of such strength as to heatsuch portion of rail to the desired degree limited by the criticalnon-magnetic temperature of the particular metal used, and suitablycooling the successive heated portions of rail, substantially asdescribed.

3. In the heat treatment of a rail according to claim 1, energizing theelectro-magnet by alternate current of high frequency to limit the depthof heating in the body of the rail under treatment, substantially asdescribed.

4. For the heat treatment of a tramway 'or other rail, heating the metalpartly by eddy currents set up therein according to claim 1 and partlyby supplementary heating means, consisting of flame. I

5. For carrying out the method of heat treating a rail according toclaim 1, apparatus comprising an alternate current electromagnet havinga core terminating in two to show, in consequence of the alteredcondition of the magnetic circuit including the magnet core and portionof rail, when the eating of the said portion of rail has reached thedesired temperature.

6. For carrying out the method of heating a rail according to claim 1, avehicle provided with a powerful alternate current electro-magneticsystem having its poles so arranged that they can be brought close tothe head of the rail to beheated so that the part oi the head adjacentto the said poles will be in the magnetic circuit of theelectro-magnetic system, means for causing alternate current of suchstrength to traverse the winding of the electro-magnetic system as toproduce in the part of the head of the rail between the said poles apowerful alternating magnetic flux that will raise such part to a hightemperature and means for cooling said heated portion of rail,substantially as described.

7. Electrical heating apparatus according to the preceding claim,wherein the electromagnetic system is of multiphase type and is adaptedto propel the vehicle by the reaction set up between it and the eddycurrents produced in the rail, substantially as described.

8. Electrical heating apparatus according to claim (3, provided with analternate current electro-magnetic system having multiple poles adaptedto act on a considerable length of the rail, said poles being graduatedin strength, substantially as described.

9. Electrical heating apparatus according to claim 6, wherein thevehicle carrying the alternate current electr0-magnet is provided withmeans for minimizing oxidation of the portion of the rail being heatedand to conserve heat and also, to prevent the cooling medium used forcooling a heated portion of the rail from coming in contact with theheated portion of the rail While in the field of the electro-magnet,substantially as described.

10. Electrical heating apparatus according to claim 6, wherein thevehicle is also provided with supplementary means for pro ducing heat,for heating to a higher temperature the successive portions of a railthat have been heated preliminarily by the electro-magnetic system,substantially as described.

11. Electrical heating apparatus according to claim (5, wherein theelectrical equipment of the vehicle comprises an electromagnetic systemadapted for use as herein set forth, a direct current supply conductorand a rotary converter adapted to receive direct current from saidsupply conductor and convert it into alternate current for use in theelectro-magnetic system, substantially as described.

12. For carrying out the method of heat ing a rail according to claim 1,the combination with a rail of a powerful alternate current electro-magnetic system having poles in close proximity to said rail, said railand elcctro-magnetic system being relatively movable in relation to oneanother in the longitudinal direction, and means for supplyingalternatecurrent to and energizing said electr -magnetic system wherebya powerful magnetic flux will be caused to pass through and heat thehead portion of said rail, substantially as described for the purposeset forth.

. 13. For carrying out the method oiheating a. rail according to claim1, the combination with a rail of a powerful alternate currentelectro-magnetic system having poles in close proximity to said rail,said rail and eleetro-magnetic system being relatively movable to oneanother in the longitudinal direction, means for supplying alternatecurrent to and-energizing said electro-magnetic system whereby apowerful magnetic flux will be caused to pass through and heat the headportion of the said rail, and an indicating device adapted to beinfluenced by the alternate current supplied to said electromagneticsystem and whereby an indication of the degree of heating of the railportion of therail under treatment can be. determined, substantially asdescribed.

Signed at London, England, this 17th day of May, 1920.

\VILLIAM MORRIS MORDEY.

